call function on javascript array only if it exists, return empty array otherwise

Question

what would be a good (concise) way in Javascript (ES6) to run a method (say, "sort") on an array only when the array exists, and return an empty array otherwise?

e.g. in this example "this.props.items" can be undefined and I don't want this to fail with "Cannot read property 'sort' of undefined":

const sortedItems = this.props.items.sort((a, b) => a.id - b.id);

(this.props.items || []).sort(...

Tushar
– Tushar

2016-10-27 03:44:00 +00:00
Commented Oct 27, 2016 at 3:44 — Tushar
– Tushar, Commented Oct 27, 2016 at 3:44

Alexander Gorelik · Accepted Answer · 2016-10-27 04:49:09Z

1

const sortedItems = this.props.items ? this.props.items.sort() : []

Basically the same as Tushar but without unnecessary sort.

answered Oct 27, 2016 at 4:49

Alexander Gorelik

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1 Comment

user663031 Over a year ago

Each unnecessary sort is likely to take less than one microsecond.

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